1. To test if participants can be recruited to consume, and adhere to, controlled diets containing varying amounts of fruit and vegetables containing dietary antioxidants for a five-week period. 2. To investigate analytic and measurement properties of markers of oxidative damage in order to plan a larger-scale intervention. 3. To obtain preliminary evidence of any effect of a fruit and vegetable intervention on markers of oxidative damage related to carcinogenesis and atherogenesis.